**Tell us what’s happening:**

I’ve tried my best to wrap my head around what this problem wants me to do, but I really don’t understand how some of the tests should return certain answers; for example the instructions say to my understanding

“if the number is not unique among the other arrays , return this value” .

However by this understanding the input

`[1, 2, 5], [2, 3, 5], [3, 4, 5]`

should return `[1,4]`

and definitely not 5, because 5 is included in every other array. What am I doing wrong?

**Your code so far**

```
function sym(...args) {
let testArr = [];
let newArr = [];
for (var i = 0; i < args.length; i++){
args[i].map(val => {
testArr.push(val);
for (var j = 0; j < args.length; j++){
if (args[j].includes(val) && args[j] != args[i]){
newArr.push(val);
}
}
});
}
let simplified = newArr.filter((val,index) => newArr.indexOf(val) == index);
let result = testArr.filter(num => simplified.includes(num) == false);
//just to sort the numbers
result.sort((A,B) => A > B);
result = result.filter((val,index) => result.indexOf(val) == index);
console.log(result);
return result;
}
sym([1, 2, 3, 3], [5, 2, 1, 4]);
```

**Your browser information:**

User Agent is: `Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.99 Safari/537.36`

.

**Link to the challenge:**

https://learn.freecodecamp.org/coding-interview-prep/algorithms/find-the-symmetric-difference/